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PH Scale/Transcript
Transcript Text reads: The Mysteries of Life with Tim & Moby. A robot, Moby, is standing behind a table. On the table is a bottle labeled “vinegar” filled with a clear liquid, and a glass filled with a clear liquid. Moby is holding a box labeled “baking soda.” He dumps some of the baking soda into the glass. (bubbling sound) The mixture in the glass begins to bubble and expand at the top into a white substance. It continues to grow and spill over the sides of the glass. MOBY: Beep. The scene changes to show a boy, Tim. TIM: Eeew. Tim reads from a typed letter. TIM: Dear Tim & Moby, how can I find the "pH" of water? From, Mrs. Douglass's class. The animation changes to show Tim and Moby standing behind a table. On the table is a bottle labeled “vinegar” filled with a clear liquid and a glass filled with a clear liquid. TIM: "pH" refers to the chemical potential of hydrogen. The pH scale measures how acidic or basic a substance is, on a scale of 0 to 14. On the acid side, which measures from 0 to 7 on the pH scale, you can find things like vinegar, lemon juice, battery acid, and the hydrochloric acid in your stomach. A diagram shows a p Upper H scale. Above the left side of the scale, text reads: acidic. Above the right side of the scale, text reads: basic left-parenthesis alkaline right-parenthesis. Fourteen vertical lines divide the scale into 15 equal sections. Each section is labeled from 0 to 14. The leftmost section is red. As you move right, the sections fade in color until the middle section at 7, which is white. The rightmost section is blue. Similarly, as you move left, the sections fade in color until the middle section. Items appear on the scale as Tim speaks. Above 6, a bottle of vinegar appears. Above 4, a lemon appears. Above 3, a battery appears. Above 1, a glass of hydrochloric acid appears. TIM: On the base, or alkaline, side from 7 to 14, you'll find things like soap, toothpaste, baking soda, and floor cleaner. Items appear on the scale as Tim speaks. Above 8 and 9, a bar of soap appears. Above 10, a tube of toothpaste appears. Above 12, a box of baking soda appears. Above 13 and 14, a bottle of floor cleaner appears. TIM: Really strong acids and bases are found on the ends of the scale, while those near the center of the scale are weaker. Right in the middle, at exactly seven, or pH neutral, you have pure water. Above 7, a glass of water appears. The scene changes to show Tim standing behind a table. On the table is a bottle labeled “vinegar” filled with a clear liquid and a glass filled with a clear liquid. TIM: Acids contain hydrogen ions while bases contain hydroxide ions. The table is removed to show just Tim. On each side of him, text appears as Tim speaks. On the left side: • Text reads: Hydrogen ions • Text reads: left-parenthesis Upper H plus right-parenthesis • Text reads: acids Then, on the right side: • Text reads: Hydroxide ions • Text reads: left-parenthesis Upper O Upper H minus right-parenthesis • Text reads: bases MOBY: Beep? TIM: What are ions? Well, they're just atoms that have either gained or lost electrons. From each side of the screen, near Tim’s head, diagrams appear. On the left side is a red sphere. Around the red sphere is a dotted circle. On the dotted circle is a blue sphere. On the right side are two red spheres. Around one of the spheres is a dotted circle. On the dotted circle are two blue spheres. Around this dotted circle is another, larger dotted circle. On this dotted circle are seven blue spheres. To the bottom left of this is a red sphere. Around the red sphere is a dotted circle that intersects at two points the larger circle around the other red sphere. There is a blue sphere at each point where the two circles intersect. TIM: In bases, you'll find hydroxide ions that have gained an electron. In the diagram on the right, a blue sphere moves from the top of the screen towards the first red sphere. It attaches to a point on the larger dotted circle. TIM: The hydrogen ions you find in acids are hydrogen atoms that have had an electron knocked off. In the diagram on the left, the blue sphere detaches from the dotted circle and moves up and out of the screen. TIM: These hydrogen ions are always trying to get their electrons back, and they steal electrons from anything handy. All of the text and the diagram to the right of Tim are removed. The diagram to the left of Tim increases in size and fills most of the background. TIM: That's why when you put something like a metal in acid, the metal starts to dissolve! The scene changes to show a screen that is split vertically into two sections. On the left side are three columns of gray spheres that fill the height of the section. Each row is shifted slightly so that it fits in the grooves of the neighboring rows. On the right side is a beaker filled with a gray colored fluid. A piece of metal moves down from the top of the screen, into the fluid. (bubbling noise) Bubbles form near the bottom of the beaker and the metal slowly decreases in size. At the same time, on the left side, small red spheres move right, towards the gray spheres. The red spheres move slowly through the gray spheres, and the gray spheres break down into gray spheres that are smaller than the red spheres. The smaller gray spheres move to the left. TIM: Bases have the power to neutralize acids. MOBY: Beep? TIM: Well, watch what happens when the two combine! The hydroxide ion gives its extra electron to the hydrogen ion. An animation shows two diagrams. In the diagram on the left is a red sphere. Around the red sphere is a dotted circle. Below this, text reads: Upper H plus. In the diagram on the right are two red spheres. Around one of the spheres is a dotted circle. On the dotted circle are two blue spheres. Around this dotted circle is another, larger dotted circle. On this dotted circle are seven blue spheres. To the bottom left of this is a red sphere. Around the red sphere is a dotted circle that intersects at two points the larger circle around the other red sphere. There is a blue sphere at each point where the two circles intersect. Below this, text reads: Upper O Upper H minus. Small circles appear below the text and start to merge and bubble. As this happens, the two diagrams merge. In the final diagram, the diagram on the left has attached to the diagram on the right so that its dotted circle intersects at two points the larger dotted circle around the first red sphere on the right. There is a blue sphere at each point where the two circles intersect. TIM: That solves the problem. The hydrogen from the hydrogen ion and the oxygen and hydrogen from the hydroxide ion combine, giving you H 2 O! The Upper H plus loses its plus sign, and the Upper O Upper H minus loses its minus sign. Then they merge together to read: Upper H 2 Upper O. Below the text, the circles and bubbles have turned into a blue fluid. TIM: That's water! And water, you remember, is pH neutral. An image shows the p Upper H scale with a picture of a glass of water above 7. TIM: Different kinds of salts are also formed, depending on the types of acids and bases involved in the reaction. Moby is standing behind a table. On the table is a glass of clear fluid. He is holding a box labeled “baking soda.” TIM: When Moby poured the baking soda, a base, into the vinegar, an acid, a reaction occurred. Moby pours the baking soda into the fluid. (bubbling sound) The mixture in the glass begins to bubble and expand at the top into a white substance. It continues to grow and spill over the sides of the glass. TIM: The vinegar broke the baking soda into a salt, water, and carbon dioxide. Carbon dioxide was what was in the bubbles. The bubbles around and inside the glass settle. There is a white substance at the bottom of the glass. MOBY: Beep. TIM: There are also substances called buffers that can block changes in their pH for a period of time. You can find them on buffered aspirin, where they keep your stomach acids from dissolving the medicine too quickly. An animation shows a round, white tablet with a cross on the top of it. A layer of the tablet is removed on one side. On the inside of the tablet, the core is light yellow. TIM: They're made by combining weak acids and bases. Buffers also occur naturally in the human body, helping our blood keep its pH at or around 7.4. The outline of a girl is imposed over the image of the tablet. A white light appears at the top of her head and moves down her body, eventually fading out. This cycle repeats. MOBY: Beep? TIM: Finding a solution's pH is easy if you have the right tools. An animation shows a small, long rectangular object. It spins and increases in size and then stops. TIM: Most science labs have a bit of pH paper lying around. TIM: These strips are soaked with a chemical indicator, and they turn red when you dip them in an acid. An animation shows a full beaker move in from the right side of the screen. On it, text reads: acid. The rectangle decreases in size and moves into the beaker so that a little more than half of it dips into the fluid, and then it is removed. The part of the rectangle that was dipped turns red. TIM: A base will make them turn blue. Then, another full beaker of fluid moves in from the right side of the screen. On it, text reads: base. Another rectangle dips into this beaker and is removed. The part of the rectangle that was dipped turns blue. TIM: Compare that color to a chart, and you can see how strong that acid or base is. The scene changes to show the p Upper H chart again. The first rectangle that turned red appears and moves from the right side of the chart towards the left, stopping near similar shades of red around 3. The scene changes to show Tim and Moby standing behind a table. On the table is a bottle labeled “vinegar” filled with a clear liquid and a glass filled with a clear liquid. TIM: pH is important outside the lab, too. Living things rely on constant pH levels in their environment. If a body of water becomes too acidic, the acids will dissolve metals into the water, and the fish in it will get sick. Fish are swimming next to a dark, cloudy substance in the water. TIM: And if acid rain caused by pollution seeps into a farmer’s soil, the crops may not grow. Rain falls on a plowed field in front of a barn and silo. TIM: The constant reactions of acids and bases keep our environment from becoming too acidic or too alkaline, which is a good thing for life in general. The scene changes to show Moby standing behind a table. On the table is a bottle labeled “vinegar” filled with a clear liquid and a glass filled with a clear liquid. Moby sticks his hand into the glass. (bubbling noise) The liquid bubbles around his hand, dissolving the metal and exposing many wires. He pulls his hand out of the liquid. MOBY: Beep! TIM: What did you do? I told you the acid would eat through metal!! The scene changes to show Tim and Moby behind the table. Moby’s dissolved hand is on the table. TIM: Oh, man, where am I going to get new parts to fix that? Moby reaches behind his back and pulls out another hand. TIM: Dad’s going to have a fit if he has to pay for yet one more repair. (metal twisting sound) The animation zooms in to show Moby attaching the new hand. It then changes to show Tim. TIM: Oh. Well. Alright, then. Do not do that again. Category:BrainPOP Science Transcripts Category:BrainPOP Transcripts